This invention relates to an information processing apparatus, an information processing system, an information processing method and a providing medium, and more particularly to an information processing apparatus, an information processing system, an information processing method and a providing medium which allow, in order to perform an isochronous transaction between different environments in which different isochronization timings are used, establishment of isochronism between the different environments by comparing time information regarding to isochronization timings and by performing time management in different environments.
Standardization activity of a bridge format in the IEEE1394 environment is being proceeded by the P1394.1 (bridge) working group (refer to the P1394.1 Draft 0.03, Oct. 18, 1997). The IEEE1394 bridge (hereinafter referred to simply as bridge) is composed of a set of apparatus called portals connected to the IEEE1394 bus (hereinafter referred to suitably as bus), so that data can be transmitted between a plurality of (two or more) buses through the bridge. Transmission of data through the bridge (between portals) can be performed using, for example, a cable, a radio wave or an infrared ray.
The bridge can be used also for transaction between a wire environment and a radio environment. For example, as shown in FIG. 6, the bridge can be used for transaction therethrough between an IEEE1394 environment (wire environment) wherein nodes 101-1 to 101-6 are interconnected by an IEEE1394 bus (or an IEEE1394 cable) and a radio environment wherein a radio system is used for exchanging data between nodes 102-1 and 102-2. In such a system as shown in FIG. 6, each node in the radio environment can be regarded as a member of the bridge. For example, in the system shown in FIG. 6, a combination of the node 102-1 and the node 101-16 can be treated as one bridge 110.
By the way, the IEEE1394 standards prescribe that one cycle of isochronous transaction is 125 xcexcs which is an interval of a cycle master node which is one of nodes connected to an IEEE1394 bus to transmit a cycle start packet. Each of the nodes receives the cycle start packet and adjusts (reset) the value (count value) of an own built-in cycle time register to establish cycle Isochronism (hereinafter referred to merely as isochronism).
However, in transaction between different environments through a bridge described above, since the reset interval (isochronization timing) of a cycle time register of each node differs from each environment (for example, the interval is 4 ms with the radio environment), matching of isochronization cannot be achieved.
It is thus an object of the present invention to provide an information processing apparatus, an information processing system, an information processing method and a providing medium which allow establishment of isochronism in isochronous transaction among different environments.
In order to attain the object described above, according to the present invention, when isochronous transaction is to be performed between different environments whose isochronization timings are different from each other, time information regarding isochronization timings of the individual environments is compared with each other, and time management between the environments is performed in response to a result of the comparison to establish isochronism between the different environments.
In particular, according to an aspect of the present invention, there is provided an information processing apparatus, including a comparison means for comparing first time information regarding an isochronization timing of isochronous transaction in a first environment and second time information regarding an isochronization timing of isochronous transaction in a second environment with each other, and a transmission means for transmitting a result of the comparison by the comparison means to another information processing apparatus of the second environment.
According to another aspect of the present invention, there is provided an information processing method, including a comparison step of comparing first time information regarding an isochronization timing of isochronous transaction in a first environment and second time information regarding an isochronization timing of isochronous transaction in a second environment with each other, and a transmission step of transmitting a result of the comparison by the comparison step to another information processing apparatus of the second environment.
According to a further aspect of the present invention, there is provided a providing medium which provides a computer-readable program for causing an information processing apparatus to execute a process including a comparison step of comparing first time information regarding an isochronization timing of isochronous transaction in a first environment and second time information regarding an isochronization timing of isochronous transaction in a second environment with each other, and a transmission step of transmitting a result of the comparison by the comparison step to another information processing apparatus of the second environment.
In the information processing apparatus, information processing method and providing medium described above, first time information regarding an isochronization timing of isochronous transaction in the first environment and second time information regarding an isochronization timing of isochronous transaction in the second environment are compared with each other, and a result of the comparison is transmitted to another information processing apparatus of the second environment. Consequently, for example, where isochronous transaction is to be performed between a wire environment and a radio environment, time information regarding an isochronization timing in the wire environment can be reflected on time information regarding an isochronization timing in the radio environment. Therefore, matching of isochronism between the two environments can be maintained.
According to a still further aspect of the present invention, there is provided an information processing apparatus, comprising a reception means for receiving comparison information between first time information regarding an isochronization timing of isochronous transaction in a first environment and second time information regarding an isochronization timing of isochronous transaction in a second environment, the comparison information being transmitted from another information processing apparatus, a correction means for correcting time information of the information processing apparatus in response to the comparison information received by the reception means, and a time management means for performing time management of the second environment in accordance with the time information corrected by the correction means.
According to a yet further aspect of the present invention, there is provided an information processing method for an information processing apparatus, having a reception step of receiving comparison information between first time information regarding an isochronization timing of isochronous transaction in a first environment and second time information regarding an isochronization timing of isochronous transaction in a second environment, the comparison information being transmitted from another information processing apparatus, a correction step of correcting time information of the information processing apparatus in response to the comparison information received by the reception step, and a time management step of performing time management of the second environment in accordance with the time information corrected by the correction step.
According to a yet further aspect of the present invention, there is provided a providing medium which provides a computer-readable program for causing an information processing apparatus to execute a process having a reception step of receiving comparison information between first time information regarding an isochronization timing of isochronous transaction in a first environment and second time information regarding an isochronization timing of isochronous transaction in a second environment, the comparison information being transmitted from another information processing apparatus, a correction step of correcting time information of the information processing apparatus in response to the comparison information received by the reception step, and a time management step of performing time management of the second environment in accordance with the time information corrected by the correction step.
In the information processing apparatus, information processing method and providing medium described above, comparison information between first time information regarding an isochronization timing of isochronous transaction in the first environment and second time information regarding an isochronization timing of isochronous transaction in the second environment transmitted from another information processing apparatus is received, and time information of the information processing apparatus is corrected in response to the received comparison information. Then, time management of the second environment is performed in accordance with the corrected time information. Consequently, for example, where isochronous transaction is to be performed between a wire environment and a radio environment, time information regarding an isochronization timing in the wire environment can be reflected on time information regarding an isochronization timing in the radio environment. Therefore, matching of isochronism between the two environments can be maintained.
According to a yet further aspect of the present invention, there is provided an information processing system, having a first information processing apparatus for performing isochronous transaction between a first environment and a second environment, and a second information processing apparatus for performing time management of isochronous transaction in the second environment, the first information processing apparatus including a comparison means for comparing first time information regarding an isochronization timing of isochronous transaction in the first environment and second time information regarding an isochronization timing of isochronous transaction in the second environment with each other, and a transmission means for transmitting a result of the comparison by the comparison means to the second information processing apparatus, the second information processing apparatus including a reception means for receiving the result of the comparison transmitted by the transmission means of the first information processing apparatus, a correction means for correcting time information of the second information processing apparatus in response to the time information received by the reception means, and a time management means for performing time management of isochronous transaction in the second environment in accordance with the time information corrected by the correction means.
According to a yet further aspect of the present invention, there is provided an information processing method for an information processing system which includes a first information processing apparatus for performing isochronous transaction between a first environment and a second environment, and a second information processing apparatus for performing time management of isochronous transaction in the second environment, comprising a comparison step performed by the first information processing apparatus of comparing first time information regarding an isochronization timing of isochronous transaction in the first environment and second time information regarding an isochronization timing of isochronous transaction in the second environment with each other, a transmission step performed by the first information processing apparatus of transmitting a result of the comparison by the comparison step to the second information processing apparatus, a reception step performed by the second information processing apparatus of receiving the result of the comparison transmitted by the transmission step of the first information processing apparatus, a correction step performed by the second information processing apparatus of correcting the time information of the second information processing apparatus in response to the result of the comparison received by the reception step, and a time management step performed by the second information processing apparatus of performing time management of isochronous transaction in the second environment in accordance with the time information corrected by the correction step.
According to a yet further aspect of the present invention, there is provided a providing medium which provides a computer-readable program for causing an information processing system, which includes a first information processing apparatus for performing isochronous transaction between a first environment and a second environment, and a second information processing apparatus for performing time management of isochronous transaction in the second environment, to execute a process comprising a comparison step performed by the first information processing apparatus of comparing first time information regarding an isochronization timing of isochronous transaction in the first environment and second time information regarding an isochronization timing of isochronous transaction in the second environment with each other, a transmission step performed by the first information processing apparatus of transmitting a result of the comparison by the comparison step to the second information processing apparatus, a reception step performed by the second information processing apparatus of receiving the result of the comparison transmitted by the transmission step of the first information processing apparatus, a correction step performed by the second information processing apparatus of correcting the time information of the second information processing apparatus in response to the result of the comparison received by the reception step, and a time management step performed by the second information processing apparatus of performing time management of isochronous transaction in the second environment in accordance with the time information corrected by the correction step.
In the information processing system, information processing method and providing medium described above, the first information processing apparatus compares first time information regarding an isochronization timing of isochronous transaction in the first environment and second time information regarding an isochronization timing of isochronous transaction in the second environment with each other, and transmits a result of the comparison to the second information processing apparatus. Then, the second information processing apparatus receives the result of the comparison transmitted by the first information processing apparatus, corrects the time information of the second information processing apparatus in response to the received result of the comparison, and performs time management of isochronous transaction in the second environment in accordance with the corrected time information. Consequently, for example, where isochronous transaction is to be performed between a wire environment and a radio environment, matching of isochronism between the two environments can be maintained.
The above and other objects, features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings in which like parts or elements are denoted by like reference symbols.